Winter moths (operophtera brumata) can be a nuisance to your trees during early spring time. The biggest concern is the larva, which is a caterpillar/inch-worm feed on the budding leaves of deciduous trees and you won't really notice it until your leaves are at their full size. A good way to get rid of the moths is with a bacterium called, BT (bacillus thuringiensis)or Spinosad a derivative of a bacterium. If you have really big trees, you may need to get an arborist to treat your trees.